Absorbent garments such as disposable diapers, adult incontinence garments, sanitary towels, training pants, and other absorbent articles are well known in the art. A disposable absorbent article is typically composed of a top layer that is adjacent to the users body and which allows liquid to move there through. A back layer is also provided that faces the clothing of the user. The back layer does not allow liquid to be transferred from the inside of the absorbent article onto the users clothing. Absorbent materials are located between the top layer and the bottom layer. The absorbent material is configured to absorb liquid and hence help to keep the skin dry.
During normal operation it is therefore the case that fluid is discharged from a user and will subsequently flow through the top layer and be absorbed by the absorbent material. The absorbent material is designed to absorb, redistribute, and store the fluid until the absorbent article is discarded. In some instances, however, fluid may come back from the absorbent material and once again contact the users skin. Such a result would occur for instance if the absorbent material were forced in a certain direction by the weight of the user, or in another instance where due to the amount and orientation of the user the fluid can not be properly absorbed. Such a result is not desired because this liquid can result in over hydration of the contacted skin and in turn create a greater chance of skin irritation for the user. In addition to simply being an irritant, excessive moisture on the skin of a user can cause, among other things, the growth of microorganisms which can undesirably lead to the onset of rashes or infection.
Tests for measuring the performance of absorbent articles have been conducted in the past. Typically the purpose of these tests were to detect early leakage of fluid from absorbent articles. Such tests consisted of constructing an apparatus which resembled a human body. The absorbent article was placed thereon. The apparatus was designed to automatically deliver a specific amount of fluid to the absorbent article. Sensors in the mannequin helped determine the location of leakage, and timers were used to record the elapsed time between the fluid dispensing and the leakage. These tests and methods treat all of the absorbent articles with the same amount of fluid. This resulted in some cases in no difference in performance between the absorbent articles. The purpose of these tests were to detect leakage outside of the absorbent article, and not to determine the location and presence of pooling within the absorbent article and on the users skin.
Other methods measure the humidity within the absorbent article. This humidity can also result in relatively high skin hydration levels, and as previously mentioned foster the growth of microorganisms within the absorbent article. Such methods make use of a hygrometer which is placed within the absorbent article or between the absorbent article and the skin in order to assess the relative humidity within the absorbent article.
It is therefore desirable to provide a method and apparatus for investigating the fluid absorption behavior of absorbent articles relative to the health and wellness of the skin that is surrounded by the articles. It is expected that the results from such a method and apparatus will aide in the design of absorbent articles which demonstrate improved leakage ability and also help to maintain the health and wellness of the skin contacted by those articles.
It is undesirable to have the portion of the absorbent article that contacts the user be wet since it means that that portion of the skin that contacts the absorbent article will also be wet. As defined herein, pooling is defined as occurring when a surface is wet. Pooling occurs when the skin of the user becomes wet. Of course, this is an undesirable situation whether it occurs for a short or a long period of time. In addition to its health consequences, pooling is also undesirable for the reason that it is uncomfortable to the user. It is therefore the case that it would be beneficial to develop a method and an apparatus to detect the location of pooling and the location of absence of pooling in designing absorbent articles such as diapers, adult incontinence articles, feminine products, and the like. Such a method and apparatus would also be beneficial in helping to design these products in order to reduce leakage and to help maintain healthy skin of the user.